1. Field of the Invention
The present invention relates to an improvement of a cleaning apparatus for removing a sputter attached to a welding torch nozzle (hereinafter, referred to as a torch nozzle) used in an arc welder using a shield gas.
2. Related Art
The cleaning apparatus for the torch nozzle mentioned above includes the apparatus which was filed as Japanese Patent Application No. 4-329979 by the applicant of this application and laid-open as Japanese Patent Unexamined Publication No. 5-269668, and the like. The cleaning apparatus is structured such that, as shown by reference numeral 1 in FIG. 6, an air nozzle body 4 forming an air suction hole 4a through a wire netting portion 3 is stood up near a bottom portion 2a disposed below a cylindrical container main body 2. An air chamber 5 is provided in the air nozzle body 4 in such a manner as to surround the air suction hole 4c in body 4. The air chamber 5 is connected to a compressed air source 7 through a solenoid valve 6 by means of a tube 8. An insertion port 9a of a torch nozzle T is provided in a cover 9 covering an upper end of the container main body 2. A discharge port 1a is formed in the main body in a freely opening and closing manner in such a manner as oppose to the air nozzle body 4, and a shield ring 10 is fixed to the lower end of the insertion part 9a.
The apparatus may be structured such that, as shown in an imaginary line in FIG. 6, a sensing switch 11 for sensing an insertion from the insertion port 9a of the torch nozzle T, is horizontally mounted to a portion near the upper end of the container main body 2 so that a front end of a contact element 11a projects into an insertion area of the torch nozzle T. The sensing switch 11 is electrically connected between a source 12a in the robot control apparatus 12 and the solenoid valve 6. This has been filed as Japanese Patent Application No. 6-129496. In this case, in FIG. 6, reference numeral 1a denotes a discharge outlet having a metal netting S attached, and reference numerals 13 and 14, respectively, denote a relief valve and a valve with a cock disposed between the solenoid valve 6 and the compressed air source 7.
Further, in the cleaning apparatus for the torch nozzle as mentioned above, for example, when the sputter becomes attached to the portion near the front end of the torch nozzle T, which is attached to the front end of a robot arm, as by performing a welding, the torch nozzle T is inserted through the insertion port 9a of the cleaning apparatus 1 by the robot control apparatus 12 which includes a power source 12a, so as to extend through the shield ring 10. The sensing switch 11 senses this and connects the solenoid valve 6 to the power source through the robot control apparatus 12. The valve is opened to an ON state, and the compressed air is communicated with the air chamber 5 by the tube 8. Accordingly, the compressed air is blown into the air nozzle body 4 from the air blowing hole 4c and is strongly injected out above the upper end of the air nozzle body 4. As a result, shot material 15 (such as a rigid ball, a broken piece of sputter, or the like), which is located in the bottom portion of the container main body 2, is sucked up by the lower end of the air nozzle body 4 and is carried by the compressed air flow from the upper end of the air nozzle body 4 and collides with the sputter attached to the portion near the front end of the torch nozzle T.
Therefore, the sputter is separated from the torch nozzle T as a ring or a broken piece so as to be dropped, and after a predetermined time has elapsed, the cleaning of the torch nozzle T is completed.
In the foregoing cleaning apparatus 1, the following problems are present.
a. Since the bottom portion 2a, which is removably mounted to the lower portion of the container main body 2, is formed in a cylindrical shape, the shot material 15 and the broken piece of the sputter dropped through the metal netting 3 are not collected in the lower portion of the air nozzle body 4, so that there is a problem in that the suction applied to the shot material 15 or the like by means of the air nozzle body 4 is deteriorated. PA1 b. The cover 9 is formed in a cylindrical shape and covers the upper end of the container main body 2 with a gap in the periphery. However, there is an inconvenience in attaching the sensing switch 11 or the like, and there is a problem that the switch or the like can not be protected from the collision with the torch nozzle or the like, for example, due to an unexpected motion of the robot. PA1 c. Since the seal ring 10 is fixed to the inner peripheral lower end of the torch nozzle insertion hole 9a formed in the middle of the cover 9 by means of a member substantially independent from the cover 9, there is a problem in the time required for attaching it. PA1 d. The discharge port 1a is provided near the upper end of the container main body 2 and the metal netting S is attached to the inside portion thereof; however, there is a problem in that the metal netting S can not be replaced even when it is soiled or is plugged. PA1 e. Since the sensing switch 11 only has a rod-like contact element 11a, there is a problem in that it is hard to detect the insertion of the torch nozzle T from the insertion hole 9a.